Heater unit



June 28, 1966 A. 'r. RACE, JR 3,258,002

HEATER UNIT Filed July 23, 1964 2 Sheets-Sheet l 1N VENTOR Aus-nNT.RHCEJIR.

ATTORNEYS June 28, 1966 A. T. RACE, JR

HEATER UNIT 2 Sheets-Sheet 2 Filed July 23, 1964 INVENTOR Aus-rm T Race39..

BY (LSMFPMJ %d cwnmed ATTORNEYS United States Patent 3,258,002 HEATERUNIT Austin T. Race, .lr., Winter Haven, Fla. Filed July 23, 1964, Ser.No. 384,698 9 Claims. (Cl. 12659.5)

This invention relates to heaters, and particularly to heaters of a typesuitable for orchard, grove, and farm use, especially in areas wheresmokeless heaters must be used.

One known practice in orchard, grove, or farm heating to protectfruit-bearing trees, plants, etc. from freeze damage, is the use of agun, or tube, type burner to throw a flame horizontally adjacent theground to provide heat for mixture with the surrounding air. A metalshell is sometimes used with the burner so that the shell will be heatedto incandescence and provide radiant heat to protect trees in thesurrounding area. While this practice provides good heating so long asthe burners function perfectly, some difficulties have been encounteredin maintaining a proper burner flame due to carbon deposits being pickedup by the velocity of the produced gaseous vapor and lodging in thenozzle orifice, some tendency toward back flow in the feed line becauseof heat and pressure in the line created by pre-heating the fuel, andmisalignment or improper position of the burner tip with respect to thepre-heating coil in those burners where the fuel line is coiled withinthe burner tube and the burner flame is directed through the coil topreheat the fuel. These factors can cause the flame to burn at a lesserrate which may cause flame fluctuation and flameout, and hot spots inthe preheater may cause the flame to pulsate.

It is the general object of the present invention to provide an improvedburner which will not be subject to the difficulties mentioned above,but will burn with a steady flame at all recommended operating pressureswith little or no attention.

A more specific object of the invention is to provide means to preventcarbon formed in the preheater coil, or other parts of the feed line,from reaching the burner nozzle.

Another object is the provision of means to retard back-flow in the fuelfeed line from heat and pressures.

Still another object is to provide for adjustment of the burner tocorrect for misalignment of the nozzle relative to the preheating coil,and to vary slightly the spacing of the nozzle from the coil.

Other objects of the invention will become apparent from the followingdescription of one practical embodiment thereof, when taken in the lightof the drawings, which accompany, and form part of, this specification.

In the drawings:

FIGURE 1 is a perspective view of a burner incorporating the principlesof the present invention, the burner being shown with a shell which maybe used for producing radiant heat;

FIGURE 2 is a vertical, longitudinal section through the burner shown inFIGURE 1, taken on the line 22 of FIGURE 1;

FIGURE 3 is a vertical, transverse section through the burner, taken onthe line 3-3 of FIGURE 2;

FIGURE 4 is another vertical, transverse section, taken on the line 44of FIGURE 2;

FIGURE 5 is a section through a back-flow arrester inserted in theburner fuel feed line, taken on the line 5-5 of FIGURE 2;

FIGURE 6 is a perspective view of the burner head carrying the burnernozzle;

FIGURE 7 is an exploded perspective view of the components of the burnerhead; and

FIGURE 8 is a longitudinal section, on an enlarged scale, through theburner head.

The heating unit shown in the drawings consists in a gun, or tube, typeburner l. A shell 2, which may be used with the burner when it isdesired to supply radiant heat, is shown as a cone of sheet metal,having an open bottom 3. A relatively large opening 4 is provided in theside, through which flame from the burner may enter to heat the metalshell. Other smaller openings 5 are present through the surface of thecone to permit the escape of gases. In operating the burner and shellcombination, the shell is placed on the ground, spaced from the outletend of the burner, with the opening 4 generally aligned with thelongitudinal axis of the burner tube. Flame, as shown at 6, from theburner enters the shell through opening 4 and impinges on the shell wallinterior, some flame and the gases of combustion passing out throughopenings 5. The heat of the flame causes the shell to becomeincandescent, and heat will radiate outward and upward from the shell.

The above described unit makes a very effective grove heater whereradiant heat is desired. The shell throws oft a great amount of radiantheat, the entire unit is very light weight and easily portable, and theradiant shell can be replaced when required without replacing the entireunit. In most instances, however, the burner is used alone as a sourceof convection heat.

The burner 1 has a tray-like base 7, upon which a housing 8 is mounted.The housing 8 has a top 9 of cylindrical curvature of more thansemi-circular extent to embrace and support a preheating coil 10. Theopen side of the partial cylinder faces downwardly, and vertical sidesllll extend from the cylindrical edges downwardly to the base. Fingers12, struck out from the sides 11, straddle the base top edges to mountthe housing. A back wall 13 bridges the housing and base. The wall 13has an inlet opening 14- for fuel from the burner nozzle. A plurality ofinlets 15 for air to support combustion encircles the fuel inlet.

The preheating coil ltl is located at the forward end of the housing,and is a part of a fuel feed line 16 which has an upper leg 17 thatextends from the rearmost convolution of the coil along the top ofhousing 8, and projects some distance to the rear of the housing andterminates in a coupling 18 for connection to a supply line 19. From thelast convolution at the inner end of the coil, the line extendsrearwardly as a lower leg 20 through the housing and back wall adjacentthe base 7. At the rear of the burner, the bottom leg is bent upwardlyfrom itself to form a forwardly projecting burner head mounting leg 21on which a burner head 22 is threaded. The heat mounting leg 21 has itsaxis approximately on the axis of the preheating coil 10.

The lower leg 20 of the fuel line, and the burner head 22 are heldagainst accidental movement from selected positions of adjustment bymeans of a clamp 23. The clamp comprises a pair of identical castings 24each having a recess 25 to seat the burner head, and recesses 26 and 27to seat the upper and lower legs 17 and 2t), respectively, of the fuelline. Bolts 28 between the upper leg 17 of the fuel line and the burnerhead, and between the burner head and lower leg 20 draw the castingstightly into engagement with the several members they engage to holdthese members against movement relative to one another. The upper leg 17of the fuel line is secured to the burner housing by means of a pipeclamp 54, and acts as the anchor member for the burner head. By clampingthe burner head intermediate the upper and lower legs of the fuel line,the head will be held against side movement and at a fixed distancebelow the upper leg of the fuel line. This permits holding the burnerhead with its Q3 axis in alignment with the axis of the preheating coil.This assures proper direction of the flame.

It will be noted from FIGURE 2 of the drawings that the last convolutionof coil at the inner end is free from the adjacent convolutions andspaced slightly from that convolution. This affords some freedom ofadjustment of the burner head to move the nozzle forward or rearward tovary the distance between the nozzle and the inlet orifice 14 in theback wall and the coil 10. Clamp 23 will hold the burner head inselected positions of adjustment.

Burner head 22 is composed of a cylindrical casing 29 having endclosures 30 and 31. End closure 30 is welded to the back end of casing29 and has a central, threaded aperture 32 to screw onto the threadedend of the mounting leg 21 of the fuel line. The cylindrical casing 29and end closure 30 form a cup, into which is inserted in succession, apad 33 of fireproof fibers, such as stainless steel, bronze, glass,etc., a first screen 34, a spacer ring 35, a second screen 36, anotherspacer ring 37 and a third screen 38 to hold the various elements inplace in the cup and to close the cup. The screens 34, 36 and 38 may beof bronze or other suitable wire having a mesh much smaller than thenozzle orifice. There is a central threaded aperture 39 in end closure31 into which a fuel nozzle 40 is screwed. The nozzle has the usualsmall outlet orifice 41. The inner face 42 of the end closure 31 has anouter annular rim 43 to bear upon screen 38, but the remainder of theface is recessed, as at 44, so that the inner end of the aperture 39 isspaced outwardly from screen 38. A short length of tube 45 is shownpressed into the entrance end of aperture 39 and extending rearwardlythrough a central opening 46 in screen 38. The tube effectively preventscarbon which may be formed by impingement of fuel on the inner face ofend closure 31 from getting into the nozzle. It will be obvious that thetube may be formed as an integral part of the end closure if desired.

Fiber pad 33 will filter much of the carbon from the fuel entering thehead, but some will pass through to be stopped by screen 34. Continueduse of the burner will cause carbon accumulation on screen 34 to thepoint where flow through would be virtually stopped if some provisionwere not made to allow continued flow-through. To this end, screen 34 isprovided with a plurality of enlarged openings 47 of a size not likelyto become clogged by carbon. With this arrangement when the mesh ofscreen 34 becomes filled with deposit, fuel with whatever sediment maybe left in it may flow freely through openings 47. Screen 36 is of thesame mesh as screen 34, but has no enlarged openings. Thus, fuel flowingfrom screen 34 will be filtered by screen 36. This provides doublefilter capacity without increasing the diameter of the burner head. Anycarbon which may be fomed by contact of the fuel with the metal of tube4-5 or the nozzle will be in an area of high velocity flow and will becarried out through the nozzle orifice before it can grow to a size toclog the orifice.

With the above described filter arrangement in the burner head, theburner may be used over long periods of time without clogging. The head,in effect, is a filter unit which also serves as a mount for the nozzle,and a means of connection between the nozzle and the fuel line. When afilter unit becomes filled with debris, the head can be unscrewed fromthe fuel line, the nozzle removed and a new unit substituted.

As previously mentioned, heat and pressure which develop during use ofthe burner will cause a tendency for backflow in the fuel line with theresult that at times there is flow in both directions and a fluctuatingflame. To overcome this, the present invention provides a backflowarrester 48 in the upper leg 17 of the fuel line. The arrester is formedby making the leg 17 of the fuel line in two sections having theiradjacent ends threaded and coupled together by a threaded sleeve 49. Ascreen 50 is seated against the end of the upstream section of leg 17,and a plug 51, having a restricted orifice 52 opening into an enlargedopen-end chamber 53, is inserted in the adjacent end of the downstreamsection of the leg. The velocity of the fuel flow through the restrictedorifice in the plug effectively retards backflow in the line.

The burner as disclosed herein Will provide long periods of trouble freeoperation and can be used without frequent checks. It is simple toadjust to maintain the burner nozzle at its proper position, and thefilter assembly in the form of a burner head is readily replaceable.

While in the above one practical embodiment of the invention has beendisclosed, it will be apparent that the specific details of constructionshown and described are merely by way of example, and the invention maytake other forms within the scope of the appended claims.

What is claimed is:

1. A heater unit comprising, a shell and a separate burner to heat theshell to give off radiant heat, the shell being a cone of thin metal andhaving an opening in the side for alignment with the burner, the burnerhaving a nozzle and support means for horizontally positioning thenozzle for alignment with and providing adjustable spacing relative tothe opening in the shell, whereby flame from the burner nozzle willenter the opening in the shell to heat the shell and the ratio ofradiant heat from the shell and convective heat from the burner can bevaried.

2. A heater unit as claimed in claim 1 wherein, the shell has additionalopenings for the escape of gases.

3. A burner comprising, a base, a housing over the base defining acombustion chamber, a fuel feed line, a burner head including a casingand end closures for the casing defining a filter chamber, the fuel lineconnected to one end closure of the burner head, a nozzle connected tothe other end closure of the burner head, a filter pad in the filterchamber adjacent the end closure to which the fuel line is connected, afirst filter screen against the filter pad, a second filter screenspaced from the first in the direction of the nozzle, both said screensbeing of similar mesh, said first screen having a plurality of enlargedpassages there-through, whereby fuel and foreign matter therein may passthrough the enlarged openings of the first screen when the mesh of thefirst screen has become clogged with foreign matter.

4. A burner as claimed in claim 3 wherein, there is a third screenspaced from the second screen and from at least the central portion ofthe end closure to which the nozzle is connected, the end closure towhich the nozzle is connected having a central aperture in which thenozzle is mounted, a tube in the said aperture and projecting throughthe third screen into the space between the second and third screen.

5. A burner comprising, a base, a housing over the base, a back wall atone end of the housing, the opposite end of the housing being open, apreheating coil in the housing adjacent the open end thereof, a fuelline connected to the ends of the preheating coil whereby the coil is apart of the fuel line, the fuel line having an upper leg extending fromthe coil along the outside wall of the housing from the open end of thehousing to the back wall and beyond, the fuel line having a lower legextending from the coil through the housing and housing back wall, thelower leg of the fuel line being turned upon itself to provide a burnerhead leg intermediate the upper and lower legs and substantially inalignment with the central axis of the preheating coil, a burner headconnected to the burner head leg, a nozzle mounted on the burner head,means securing the upper fuel line leg to the housing, and a clampengaging the upper fuel line leg and the burner head to hold the nozzlein alignment with the axis of the preheating coil.

6. A burner as claimed in claim 5 wherein, the clamp also embraces thelower fuel line leg to hold the upper, lower and burner head fuel linelegs in a common vertical p ane.

7. A burner as claimed in claim 6 wherein, the clamp includes companioncastings having recesses to receive the upper, lower and burner headfuel line legs, and means to draw the castings toward one another inclamping engagement with said fuel line legs.

8. A burner comprising, a base, a housing over the base, a preheatingcoil in the housing at one end thereof, a nozzle at the opposite end ofethe housing from the coil, a fuel line connecting one end of the coilWith the nozzle, a fuel line connected to the opposite end of the coiland extending along the outer surface of the housing and projectingbeyond the end of the housing in which the nozzle is located, and aback-flow arrester in the projecting portion of the fuel line, the backflow arrester including a plug seated in the projecting portion of thefuel line, the plug having a restricted orifice therein.

9. A burner as claimed in claim 8 wherein, there is a screen bridgingthe fuel line upstream of the plug.

References Cited by the Examiner UNITED STATES PATENTS 1,304,045 5/ 1919Hill. 1,582,621 4/ 1926 Roberts. 2,097,544 11/1937 Ames 126-59.52,373,588 4/ 1945 Meiklejohn. 2,463,830 3/1949 Tullis 15853 2,467,450 4/1949 Wollner 15 879 FOREIGN PATENTS 1,216,387 11/1959 France.

CHARLES J. MYHRE, Primary Examiner.

1. A HEATER UNIT COMPRISING, A SHELL AND A SEPARATE BURNER TO HEAT THESHELL TO GIVE OFF RADIANT HEAT, THE SHELL BEING A CONE OF THIN METAL ANDHAVING AN OPENING IN THE SIDE FOR ALIGNMENT WITH THE BURNER, THE BURNERHAVING A NOZZLE AND SUPPORT MEANS FOR HORIZONTALLY POSITIONING THENOZZLE FOR ALIGNMENT WITH AND PROVIDING ADJUSTABLE SPACING RELATIVE TOTHE OPENING IN THE SHELL, WHEREBY FLAME FROM THE BURNER NOZZLE WILLENTER THE OPENING IN THE SHELL